5 players Arsenal should target in the January transfer window

#4 Kalidou Koulibaly (Centre-Back)

Kalidou Koulibaly - a ball-playing defender Arsenal can rely on

Arsenal can no longer rely on the current crop of defenders in the squad due to a combination of age and fitness issues. And with Per Mertesacker retiring at the end of the season, the Gunners must look to replace him with a top quality centre-back.

Unfortunately, Calum Chambers has barely grown in the past few seasons and Wenger's reluctance to use him in big games proves he is not entirely convinced with the Englishman's progress.

Laurent Koscielny is not getting any younger and his Achilles injury prevents him from playing more than once a week without experiencing discomfort. Shkodran Mustafi's injury niggles keep cropping up leaving Nacho Monreal (a converted centre-back) as the only reliable option at the back.

Enter Kalidou Koulibaly. The Napoli centre-back is one of the best ball-playing defenders in Europe at the moment and has been key to the Serie A club's build-up play from the back. No defender in Europe has complete more short passes than the Senegalese centre-back.

However, he will not come cheap, what with a contract until 2021. And the fact that Chelsea are also interested in securing his services makes it tough for Arsenal to get their man.